Is there a delay between loading winds and seeing the "W"?

[skelsey]

In PSX the W is blank because the whole ETA/fuel text block on the RTA DATA page is blank. In real life you would first complete your PERF INIT before requesting wind/OAT data. So I don't know whether the real FMC would show the "W".

Hi Hardy,

Actually, I don't think the wind data uplink will work at all unless the PERF INIT and critical data (i.e. V speeds and TAKEOFF REF pages etc) is completed, at least according to the following note in the FCOM:

ACT RTE DATA page.................................................................... Select
• Select Wind REQUEST
• Load and execute en route winds
• Load descent forecast winds
Note: No environmental data will be uplinked to the FMC unless the
Critical Data Procedure is completed before making a wind data
request.

[Hardy Heinlin]

Good point. I guess this is because the wind data preparation needs the initial CRZ ALT. If so, this requirement in the dispatch system might be airline specific though. In PSX 10.93 (not uploaded yet) I implemented the logic used in Lufthansa: If zero or four wind altitudes are entered in the FMC, the dispatch system will ignore them and compute four altitudes on its own and uplink these. Otherwise it will take the pilot entered altitudes only. By applying this trick, the crews can get data for more waypoints for less altitudes within the 1250 byte limit, e.g. for 120 waypoints at 2 altitudes instead of 60 waypoints at 4 altitudes.


Regards,

|-|ardy

[emerydc8]

When tried on a 767, there is about a 6-second delay between pressing load and seeing the Ws. Is this what you're talking about?

https://www.youtube.com/watch?v=p263qaWZruM&feature=youtu.be

[Hardy Heinlin]

Yes, it belongs to the subject we're talking about.